By the mid-1960s Mr. Cohran had spent three years playing trumpet and cornet in the pioneering Sun Ra Arkestra, and was established as both a bandleader in his own right and a galvanizing force on the Chicago scene. On May 8, 1965, his birthday, Mr. Cohran and three other local musicians called a meeting at his home in response to a series of nightclub closings, part of a broader economic downturn in the city’s black community.

In a series of meetings that month, the group established the A.A.C.M., whose goal was to create original music and raise public consciousness through performances and events on the South Side.

He later left the organization because, he said, he had been uninspired by its focus on free improvisation. But the A.A.C.M. thrived, becoming an internationally known symbol of the avant-garde and artistic self-reliance. It still exists.

In 1967, Mr. Cohran formed the Artistic Heritage Ensemble, a large group whose trancelike, communitarian music seemed to unite modern funk with Southern ring shouts, and both big-band and experimental jazz. The outdoor concerts he organized at the 63rd Street Beach, where dance troupes performed and vegetarian food was sold, became a citywide phenomenon, with crowds often numbering in the thousands.

The poet Gwendolyn Brooks memorialized these events, which came to be known as the On the Beach concerts, in “The Wall”:

Women in wool hair chant their poetry.Phil Cohran gives us messages and musicmade of developed bone and polished and honed cult.It is the Hour of tribe and of vibration,the day-long Hour.

The Artistic Heritage Ensemble released a number of albums on Mr. Cohran’s Zulu Records. Its first, “On the Beach,” was reissued in 2001 by Aestuarium Records and is considered part of the avant-garde canon.

For all his life Mr. Cohran was a ravenous autodidact, studying world history, astrology, health science and musicology and passing that knowledge on to students. He also constructed instruments, including what he called the Frankiphone, an amplified version of the West African mbira, or thumb piano.

Mr. Cohran belonged to a generation of artists who exhumed vast amounts of cultural history that had been widely suppressed since the beginning of the trans-Atlantic slave trade. Speaking of his early forays into African history, he told the art historian Rebecca Zorach in 2011, “It was like discovering a gold mine in the garbage can.”

Philip Thomas Cohran Jr. was born on May 8, 1927, in Oxford, Miss., the only child of Philip Thomas Cohran and the former Frankie Mae Green. He moved with his parents to St. Louis when he was in elementary school.

After briefly attending Lincoln University in Jefferson City, Mo., he returned to St. Louis, where he played trumpet in blues and jazz bands and eventually started his own 12-piece ensemble, the Rajahs of Swing. He joined the pianist Jay McShann’s big band in January 1950, but was soon drafted. He performed with a Navy band stationed in Maryland.

After leaving the Navy, Mr. Cohran moved to Chicago in 1953. Five years later the pianist and composer Sun Ra invited him into the Arkestra, a path-blazing ensemble that presaged multiple strains of avant-garde jazz and Afro-Futurist art. Sun Ra’s distinctive blend of rigorous musical practice, historical inquiry and philosophic soliloquies made an impression on Mr. Cohran.

The band’s effect on audiences “was proof that music had that power over people whether they’re conscious or not,” he told the magazine The Wire in 2001. “It gets inside of your body, inside your body rhythms, it mixes with your chemistry.”

The Arkestra moved to Montreal in the spring of 1961, but Mr. Cohran decided to stay in Chicago. He formed his own group, the Story Tellers, and performed with Experimental Ensemble, led by the pianist Muhal Richard Abrams, who would also become a founder of the A.A.C.M.

In 1967, he started the Affro-Arts Theater, a short-lived but influential gathering place that hosted speeches, conferences and concerts, as well as classes in foreign languages, music, health and history. The Artistic Heritage Ensemble performed there each weekend.

A young Chaka Khan took classes and gave some of her first public performances at the theater. Maurice White took Frankiphone lessons and incorporated the instrument into his work with Earth, Wind & Fire, which he founded in 1970. Abbey Lincoln, Betty Carter and Harry Belafonte all performed there, or simply came to listen. The theater closed in late 1968, after its leadership clashed with city officials.

In the mid-1970s, Mr. Cohran operated Transitions East, a music venue and health food store. For most of the 1980s he ran the Sun Ark, a venue that continued the mission of the Affro-Arts Theater.

The percussionist Kahil El’Zabar studied with Mr. Cohran as a teenager and eventually became a leader of the A.A.C.M. “He had learned from many examples and developed his own pedagogy,” Mr. El’Zabar said in an interview. “It wasn’t only music; it was very much about the musician being an instigator and agitator and a visionary.”

In 2004, eight of Mr. Cohran’s sons formed the Hypnotic Brass Ensemble, a nationally known band that incorporates elements of jazz, R&B and hip-hop.

Mr. Cohran is survived by 23 children from multiple relationships, as well as 37 grandchildren and 12 great-grandchildren.

In the 1980s, Mr. Cohran led Artists for Harold Washington, which worked to elect Chicago’s first black mayor. While touring China in the 1990s, he met with a group of Muslims who gave him the name Kelan, meaning “holy scripture.”

On Mr. Cohran’s 90th birthday this spring, the Jazz Foundation of America gave him its annual lifetime achievement award at a ceremony in Chicago. On July 9, a celebration of the 50th anniversary of the first On the Beach concert is set to take place at the 63rd Street Beach.

A version of this article appears in print on , on Page B11 of the New York edition with the headline: Kelan Philip Cohran, 90, a Musician Who Sought to Galvanize Chicago. Order Reprints | Today’s Paper | Subscribe